@debugninja I'd say you could either take a look at #opensuse kiwi if you want something high level. Otherwise you should start with writing an package manager (or use rpm) and installer. Some basic packages you need are
* the kernel
* a shell
* bsdtar
* gcc + tools
* gnu coreutils / busybox
* dhcpcd / networkmanager
* init system (systemd / OpenRC) but you could also start with bash as pid 1.

Im missing a few things, just get inspired by LFS packages.